He's not being stubborn about the stairs.

You know the moment. He walks to the bottom, stops, and looks up. Two years ago he'd have been at the top already. Now there's a pause — short, but it's there every single time.

Then the floors. On carpet he's fine. On the kitchen tile his back paws slide out sideways and he has to re-plant them. You've watched him do the slow-motion sit, lowering himself down in stages like he's testing whether the floor will hold.

And the part almost nobody says out loud: you've started helping him up. A hand under the back end, a lift into the car, a hoist onto the bed. It became part of your routine so gradually you can't remember the first time you did it.

Here's what owners notice and can't explain. His front end looks fine. Shoulders still solid. Chest still strong. He'll still put his paws up on you like he always did.

It's only the back half.

That's the detail that tells you this isn't random. If age were just wearing him out evenly, it would show up everywhere at once. It doesn't. It starts in one specific place, in the same order, in almost every dog.

There's a reason for that order — and it isn't in the joint.

• He pauses at the bottom of the stairs before going up
• His back paws splay out on hardwood or tile and he has to re-plant them
• He does the slow-motion sit — lowering down in stages instead of one movement
• You put a hand under his back end to help him rise, and you do it daily now
• He puts his front paws on the couch and waits instead of jumping
• His front end still looks strong — shoulders and chest haven't changed
• You already tried a joint chew or a glucosamine powder, and nothing happened

If that last one hit, read this part carefully, because it's the one owners get wrong about themselves.

Here's the order nobody explains. Dogs lose muscle as they age — vets call it sarcopenia — and it can begin as early as seven or eight, earlier in big breeds. The front end tends to hold. The back end goes first.

The back legs carry the biggest muscles in the body and do the pushing. Every stair, every jump, every rise off the floor starts there. They also hold more of the fast, powerful muscle fibers — the ones that fade earliest — and they sit at the end of the longest nerve pathways a dog has.

Biggest muscles. Heaviest job. Longest wiring. That's why they show it first.

And it's muscle, not just joint. Which is why a supplement built entirely around cushioning a joint can be a fine product and still do nothing for the thing you're actually watching.

One more thing that matters. Not every back-leg change is muscle loss. Some are medical conditions that look almost identical and need a vet, not a supplement. If it came on fast, or one side is clearly worse, get him seen first.

Most owners reading this have already spent money here. A bag of chews. A glucosamine powder. Maybe two or three different brands over a couple of years, each one bought with real hope.

And then nothing changed, and somewhere in the back of your mind you decided that was on you. You didn't give it long enough. You picked the cheap one. You should have researched harder.

Almost none of that is true. There are two much simpler explanations, and neither one is your judgement.

First: the joint wasn't the whole problem. A joint doesn't move itself — muscle moves it. Cushioning a joint does nothing for muscle that's short on fuel.

Second: most of it never got in. A lot of what you pour on dinner doesn't survive the trip. Stomach acid, first-pass loss in the liver, ingredients that barely dissolve. The label says one number and the muscle cell gets a much smaller one. A pill he spits out is a zero dose — but a pill he swallows can still be close to one.

Underneath both is the same thing. Muscle cells are packed with mitochondria, tiny power plants that turn food into usable energy. They run on a helper molecule called NAD+, which naturally declines with age — and drains faster in older cells, because an enzyme called CD38 climbs over time.

Less fuel made. More fuel lost. And the first place a low battery shows is the biggest muscles doing the hardest work.

Pawprint Protocol was built by owners who had already tried the joint route and wanted to know what was underneath it.

Working with veterinary advisors, they built a daily liquid around one job: give muscle cells the building block they use to make NAD+, and get it there in a form that actually absorbs.

The lead active is NMN — the direct building block for NAD+, and the only active in this formula with published dog research behind it. Oral NMN has been studied in dogs and raised NAD+ levels in the liver.

Then the delivery, which is the part that decides everything. Pawprint Protocol is a nanoliposomal liquid, not a pill or a chew. Each active is wrapped in a tiny protective layer so it survives the stomach and gets taken up — up to 98% absorption.

And it's a few drops on whatever he already eats. No pill pockets. No cheese. No chew he has to agree to.

Owners tell us the first sign isn't the stairs. It's the moment they realize they haven't put a hand under his back end all day.

The senior shelf at any pet store is a wall of the same promise: cushion the joint, drop the stiffness. If that promise had worked for your dog, you wouldn't be reading this.

Pawprint Protocol works one level below the joint — at the muscle cell that has to power every push those back legs make. A few drops of liquid on his food, once a day.

Four actives, each with a job:

• NMN: The direct building block cells use to make NAD+, the fuel-helper molecule that naturally declines with age. This is the hero, and the one with published dog research behind it.
• NAD+: Included as part of the same pathway, supporting the cellular energy system the rear muscles run on all day.
• Resveratrol: A plant compound studied alongside NAD+ for its role in the cell's energy and repair signaling.
• CoQ10: Sits inside the mitochondria — the tiny power plants in muscle cells — where energy actually gets made.

All four in a nanoliposomal liquid, because an ingredient that doesn't get absorbed is a line on a label, not a dose.

✔ Supports muscle and mobility in aging back legs
✔ Supports the cellular energy that naturally declines with age
✔ Up to 98% absorption — built to be absorbed, not just swallowed
✔ Works alongside any food (kibble, raw, fresh, home-cooked)

Made for dogs 7 and up. Individual results may vary.

You don't have to wait three months to see anything. Most owners tell us the first changes show up in days to weeks — and they almost always show up as one less thing you have to do for him. Here's the pattern owners describe most often. Individual results may vary.

Small, and easy to miss if you're watching the stairs. He gets up off the floor on the first try instead of the second. The slow-motion sit speeds up. One owner told us the thing she noticed first was catching herself reaching to help him stand — and finding he was already up.

This is usually where the pause at the bottom shortens, then quietly disappears. The couch comes back — up on the first try instead of paws-up-and-wait. Walks stretch out because he didn't turn for home, not because you pushed him further.

Owners often mention hardwood here. Less scrabbling. Fewer moments where the back paws slide out and have to be re-planted. He walks across the kitchen instead of hugging the runner. Good days stop being events and start being most days.

For most families this is the one they actually notice: they haven't put a hand under his back end in weeks, and they can't say exactly when that stopped.

Three months in, the job changes from noticing to keeping. Muscle loss doesn't pause and NAD+ keeps declining with age, so the dogs who hold their ground are the ones who stay on it.

And it's worth saying plainly: the earlier a dog starts, the more muscle there is to support. Individual results may vary.

Weak back legs aren't the start of this. They're the part you could finally see.

Everything before that — the shorter walk, the slower rise, the pause on the tile — was the same thing showing up quietly. The muscle didn't quit on him. It ran low on the fuel it needed to do the heaviest job in his body.

That's supportable. And it starts with a few drops on dinner tonight.

Reviews are unedited excerpts from verified Trustpilot reviews of Pawprint Lab. Individual results may vary.

[1] You, J. et al. Subacute Toxicity Study of Nicotinamide Mononucleotide via Oral Administration. Frontiers in Pharmacology, 2020.

[2] Camacho-Pereira, J. et al. CD38 Dictates Age-Related NAD Decline and Mitochondrial Dysfunction Through an SIRT3-Dependent Mechanism. Cell Metabolism, 2016.

[3] Obesity and Sarcopenia Affect the Metabolite Profiles of Pet Dogs. bioRxiv, 2025.

[4] Mitochondrial Aging and Age-Related Dysfunction of Mitochondria. BioMed Research International, 2014.

[5] Increased Oral Bioavailability of Resveratrol by Nanoparticle Encapsulation. Journal of Nanobiotechnology, 2018.

[6] Age-Dependent Decline of NAD+ — Universal Truth or Confounded Consensus? Nutrients, 2022.